Bones of Skull

Skull is the skeleton of the head consisting of the cranium and mandible. It encloses the brain and supports the face. Total number of bones in the skull is 22, as is discussed in detail below.

Cranial part of the skull is composed of several separate bones united at immobile joints called sutures, which are held by sutural ligaments. Contrary to this, the mandible is united to the cranium by a mobile synovial joint called the temporomandibular joint.

Structure of skull bones:

Skull bones are made up of external and internal tables of compact bone separated by a layer of spongy bone called the diploe. The internal table of compact bone is thinner and more brittle than the external table. The bones are covered on the outer and inner surfaces with periosteum.

Divisions:

Bones of skull can be divided into two groups: Bones of cranium, Bones of Face. The vault of skull is the upper most part of the cranium and the base of skull is the lower most part.

Bones of cranium:

The cranium consists of the following bones (Note: Number of bones is shown in bracket):

  • Frontal bone (1)
  • Parietal bones (2)
  • Occipital bone (1)
  • Temporal bones (2)
  • Sphenoid bone (1)
  • Ethmoid bone (1)

It is evident from the above list that there are only two paired bones in the cranium.

Bones of face:

Facial bones consist of the following (Note: Number of bones is shown in bracket):

  • Zygomatic bones (2)
  • Maxillae (2)
  • Nasal bones (2)
  • Lacrimal bones (2)
  • Vomer (1)
  • Palatine bones (2)
  • Inferior conchae (2)
  • Mandible (1)

It is evident from the above list there are only two unpaired bones in the face.